LimeWire hangs my Ubunutu

[Osama I. Dosary]

Hello,
After a few minutes of starting LimeWire my machine becomes very very 
slow. Then when I leave it for more than 20 minutes in this state, it 
fully hangs. Usually I get a frozen screen/keyboard/mouse.

Machine specs: P4-3GHz, 1GB RAM, ~20GB free on partition.

Stats before starting LimeWire:

 top - 09:07:05 up  1:10,  6 users,  load average: 0.01, 0.05, 0.13
 Tasks:  81 total,   1 running,  79 sleeping,   0 stopped,   1 zombie
 Cpu(s):  3.0% us,  0.7% sy,  0.0% ni, 96.0% id,  0.0% wa,  0.3% hi,  
0.0% si
 Mem:   1036504k total,  1020500k used,    16004k free,    52632k buffers
 Swap:  3903784k total,        0k used,  3903784k free,   812164k cached
   PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
  7385 dosary    15   0 33020  14m 8236 S  2.7  1.4   0:04.17 gnome-terminal
  6177 root      15   0  157m  26m 8288 S  0.7  2.6   1:02.97 Xorg
  9135 dosary    17   0  2080 1048  824 R  0.3  0.1   0:03.92 top
 ...
dosary at ubi:~$ free
             total       used       free     shared    buffers     cached
 Mem:       1036504    1020524      15980          0      52632     812164
 -/+ buffers/cache:     155728     880776
 Swap:      3903784          0    3903784

dosary at ubi:~$ vmstat
 procs -----------memory---------- ---swap-- -----io---- --system-- 
----cpu----
  r  b   swpd   free   buff  cache   si   so    bi    bo   in    cs us 
sy id wa
  3  0      0  15980  52632 812164    0    0   241    31 1199   569  5  
1 79 15


About one minute from starting LimeWire:

 top - 09:08:50 up  1:12,  6 users,  load average: 2.19, 0.64, 0.32
 Tasks:  84 total,   1 running,  82 sleeping,   0 stopped,   1 zombie
 Cpu(s): 14.6% us,  3.0% sy,  0.0% ni,  0.0% id, 80.1% wa,  0.3% hi,  
2.0% si
 Mem:   1036504k total,   490632k used,   545872k free,    53828k buffers
 Swap:  3903784k total,        0k used,  3903784k free,   241296k cached
   PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
  9238 dosary    16   0  179m  53m  19m S  8.0  5.3   1:21.69 
mozilla-thunder
  9390 dosary    15   0  341m  57m  21m S  8.0  5.6   0:11.69 java
  6177 root      15   0  159m  27m 8680 S  0.7  2.7   1:04.92 Xorg
 ...

dosary at ubi:~$ free
             total       used       free     shared    buffers     cached
 Mem:       1036504     588440     448064          0      53972     324444
- /+ buffers/cache:     210024     826480
Swap:      3903784          0    3903784
 
dosary at ubi:~$ vmstat
 procs -----------memory---------- ---swap-- -----io---- --system-- 
----cpu----
  r  b   swpd   free   buff  cache   si   so    bi    bo   in    cs us 
sy id wa
  4  3      0 382084  54076 401276    0    0   288    31 1210   618  5  
1 76 18

I notice that the used Swap is ZERO. How can that be, when the Java 
process is using 341MB of Virtual memory, with only 19MB resedent 
memory. VIRT = SWAP + RES (from 'top' man-page), which means that 322MB 
of swap must be used, so why isn't 'top' showing the swapping. ... I'm 
confused. And is this related to the hangs?

Does anyone have any ideas about what is going on, or how I can fix it?

TIA,
Osama